Set Up a Riemann Sum Approximating the Volume of the Torus

Multiple Choice

Set up a Riemann sum approximating the volume of the torus (donut) obtained by rotating the circle $(x-6) ^{2}+y^{2}=1$ about the y-axis.

A) $\sum \pi\left(6+\sqrt{1-y^{2}}\right) ^{2} \Delta y$
B) $\sum \pi\left(6-\sqrt{1-y^{2}}\right) ^{2} \Delta y$
C) $\sum \pi\left(\left(6+\sqrt{1-y^{2}}\right) ^{2}+\left(6-\sqrt{1-y^{2}}\right) ^{2}\right) \Delta y$
D) $\sum \pi\left(\left(6+\sqrt{1-y^{2}}\right) ^{2}-\left(6-\sqrt{1-y^{2}}\right) ^{2}\right) \Delta y$